1. Field
Embodiments of the present invention generally relate to methods for forming a flowable carbon-containing film on a semiconductor substrate.
2. Description of the Related Art
Semiconductor device geometries have dramatically decreased in size since their introduction several decades ago. Modern semiconductor fabrication equipment routinely produce devices with 45 nm, 32 nm, and 28 nm feature sizes, and new equipment is being developed and implemented to make devices with even smaller geometries. The decreasing feature sizes result in structural features on the device having decreased width. The widths of gaps and trenches on the devices are narrow such that filling the gap with dielectric material becomes more challenging. The depositing dielectric material is prone to clog at the top before the gap completely fills, producing a void or seam in the middle of the gap.
Over the years, many techniques have been developed to avoid having dielectric material clog the top of a gap, or to “heal” the void or seam that has been formed. One approach has been to start with carbon-containing flowable material that may be applied in a liquid phase to a spinning substrate surface (e.g., SOG deposition techniques). After removing solvent, a carbon-containing film is formed in the trenches. The carbon is then removed from the film to form air gaps inside the trenches. However, the carbon in the carbon-containing film formed by SOG deposition techniques is very difficult to remove.
Therefore, an improve method for forming a flowable carbon-containing film on a substrate is needed.